i7 16GB ram 64bit Win 8.1 Staff very helpful with checking there would be available slots to take my existing pci cards. Computer performs well. Adobe Lightroom 5.6 gets very heavy use and is very stable. Cubase 7.5 only used lightly but also very solid. (Supplied Microsoft qwerty keyboard is very spongy and takes a lot of pressure to register keystrokes.) Main gripe is that computer arrived in a damaged box and there was a minor dent in the computer case. This may well have been the fault of the courier but took the shine of the buying experience. If this hadn't happened I would have given 5 stars.